Prosodic prominence in a stressless language: An acoustic investigation of Indonesian

Although it has been proposed that all languages may have some lexical stress property, recent studies of (Standard) Indonesian have concluded, based primarily on perception, that lexical stress is not present in this language. While it is philosophically problematic to prove the non-existence of a phenomenon, we examine data from a large-scale production study for both direct and indirect evidence of stress, contributing to the growing body of literature in this field. In the first case, evidence is sought that indicates that a particular syllable in a word exhibits acoustic properties typically associated with prominence (i.e. fundamental frequency (f0), duration, intensity, vowel quality). In the second case, evidence of enhancement of these properties on a particular syllable under focus is sought, for a more abstract stress property that is not overtly manifested at the word level. Although we find no evidence of lexical prominence, we observe acoustic patterns consistent with a higher level prominence corresponding to focus, manifested by strong (Intonational Phrase) boundary properties. Overall, our findings reveal that there is strong support for a class of languages lacking lexical stress, and in the absence of a stressed syllable to enhance, focus may be manifested prosodically as boundary properties.